1. Field of the Invention
The invention relates to an articulation mechanism having a center part and a head part, particularly for lounge chairs such as garden lounge chairs or camping beds.
2. Description of the Related Art
Lounge chair articulation mechanisms are provided in order to connect a head section with a lounge chair frame in a pivotable way and to foldably connect a leg part that serves as a support to the lounge chair frame. The head section is to be adjustable in several angular positions relative to the remaining lounge chair surface. In the case of known lounge chair articulation mechanisms, it is first required to fold out the leg part before pivoting of the head section relative to the remaining part of the lounge chair is carried out. However, this operational sequence is not always ensured and, when the articulation mechanism is accidentally mishandled, the head section must be folded back and the leg part must then be moved into its supporting position.
It is an object of the present invention to provide an articulation mechanism, particularly for lounge chairs, which is of a simple configuration but can still be safely and reliably handled.
In accordance with the present invention, this is achieved in that the articulation mechanism, particularly for lounge chairs, comprises a central part and a head part, wherein the head part and the central part are comprised of shaped elements interacting in pairs and having sockets formed thereon. One of the shaped element pairs is configured as inner shells and the other shaped element pair is configured as outer shells, wherein the shaped element pairs are pivotable relative to one another and are lockable relative to one another in one movement direction in several positions. The outer shells have inwardly oriented projections; between the inner shells a movable slide is arranged. Teeth are formed on the slide and act as locking members which project through openings in the inner shells and engage intermediate spaces of the projections of the outer shells. The slide is biased by a spring in the engagement direction of the locking members. The shape of the projections is such that the locking members automatically reach a locking position in one pivot direction of the head part.
The articulation mechanism according to the present invention is characterized, inter alia, in that it is comprised of a very small number of shaped elements that can be easily manufactured and easily mounted. Depending on the required force acting as torque on the slide, the teeth can be sized accordingly.
Instead of two locking members, additional locking members in the form of teeth neighboring the spring can be provided or the locking members themselves can be reinforced by providing for the slide a material with higher strength or by manufacturing the slide of a thicker material. The slide comprises a bent section so that the slide extends laterally adjacent to a rivet which forms a pivot axis of rotation of the shaped element pairs of the center part and the head part that are pivotable relative to one another.
In a preferred embodiment of the invention, on the outer shells several projections are arranged in a first group and the same number of projections of a second group are positioned diametrically opposite to the projections of the first group. Between the projections, intermediate spaces with identical contact surfaces and/or glide surfaces for the slide or its elements are formed. These groups with differently shaped projections and thus also different intermediate spaces. This makes it possible that one of the groups provides a locking action and enables in one direction a forward movement with catch action, while the projections of the other group provide only a locking action and thus a force transmission. The projections of the first group each have a slanted surface on which a leading edge of the slide glides upon pivoting of the head part in one pivot direction.
In order to lock the slide as needed such that it can be locked with regard to movement in its longitudinal direction upon certain pivot movements of the head part relative to the center part, measures can be provided by which the slide, i.e., its teeth neighboring the spring, is moved transversely to the longitudinal direction of the slide and engages behind a step of the corresponding opening of the inner shell. In addition, or as an alternative, the slide is provided on a lateral edge with an additional tooth which engages a guide slot in one of the inner shells, wherein the guide slot has a section on which a step is formed. Such a configuration of the additional tooth should be provided particularly in such arrangements in which only the leading end of the slide is provided with locking members. In order to lock the slide relative to its longitudinal movement in a certain angular position of the head part relative to the center part, or to release the locking action in a different angular or pivot position, additional projections are formed on the outer shells, wherein it is expedient that one of these additional projections is correlated with the first group of projections and the other additional projection is correlated with the other group of projections.
The spring is simply arranged in a socket formed by the shaped elements wherein the spring is supported on a spring stop which is formed as a unitary part of the shaped elements.
According to a preferred embodiment, the articulation mechanism according to the invention is provided with a leg part which is supported pivotably on the center part.
The leg part is comprised preferably of a hollow profiled section which has at its end two parallel wall parts with congruent bores for receiving a component serving as a pivot axis, wherein these wall parts serve for forming a hinge together with the shaped element pair that forms the center part. In a preferred embodiment, a first outer shell of a shaped element pair is provided with a shaped portion which cooperates with a wall part forming the hinge. This shaped portion is preferably essentially shaped like a circular segment and on the first wall part a concave gliding contour is formed having a curvature that is matched to the radius of the circular segment.
In order to ensure that the head part can not be folded out away from the center part before the leg part has been moved into the folded-out position, it is expedient that a second outer shell of a shaped element pair has a unitary projecting member which extends in the axial and radial direction and that the second wall part of the leg part has such a contour that, depending on the pivot angle of the leg part, the projection cooperates with the wall part or is released. Depending on the shape of this wall part, it may also be possible that the leg part is first pivoted open by a certain pivot angle and the remaining pivoting action is realized in a forced way simultaneously with the folding action of the head part away from the center part.
In an expedient configuration, the center part has correlated therewith the inner shells and the head part has correlated therewith the outer shells. Of course, it is also possible to reverse this arrangement, i.e., the outer shells are components of the center part. In order to prevent damage to the articulation mechanism by penetration of sand, dirt or the like, the inner hollow space containing the movable parts should be sealed off relative to the exterior. It is therefore expedient to provide the inner shells each with a rim oriented toward one another so that a contour closed off to the exterior is provided.